What is stereo?




There are now two system of high fidelity, monophonic (monaural) and stereophonic. Monophonic is a system that starts from one microphone and is fed through a single high fidelity set. Stereophonic is a double system. Two separate microphones are placed at different sides of the orchestra and two different systems are used to keep the two signals or channels separated. Two separate speakers are used, placed on different sides of you room. Stereo is much like 3-D photography, two slightly different sound reach your ears giving you a new dimension in sound.




H.H. Scott '59





Marantz PM-300 amplifier

The Marantz PM-300 is a stereo amplifier that is FTC rated for 4 ohms at 37 watts per channel, 20 Hz to 20 kHz, at no more than 0,08% Total Harmonic Distortion. At the usual speaker impedance of 8 ohms the rated FTC output power was 30 watts per channel. Overall, this is a nice, moderate cost unit suitable for smaller installations. The output power meters, though having essentially a flat frequency response, had acceptably accurate readings only when the output power was 6 watts 8 ohms, or higher. The meters are calibrated from 0 to 60 watts into 8 ohms and from 0 to 120 watts into 4 ohms. Its equalization of 50 Hz; 1,000 Hz and 10,000 Hz. There is also a 20 Hz low filter. Another convenience feature is the single switched and unswitched AC outlets. In our specifications we show the power output measured into an 8 Ω load to be 3 watts more than the manufactures claimed rating. Marantz emphasises the 4 Ω rating because they say speaker impedances are usually 5-6 ohms, not 8 ohms.
Specifications:
Power Output Rating per Channel:
37 W at 4 Ω RMS
33 W at 8 Ω RMS
Total Harmonic Distortion (at RMS 8 Ω):  0,025%
Intermodulation Distortion:  0,03%
Damping Factor:  60 (8 Ω , 1 kHz)
Frequency Response:  15 Hz - 50 kHz
Signal-to-Noise Ratio: 
Phono :  87 dB
Line :  98  db
Input Sensitivity/ Impedance: 
Phono :  2,8 mV/47 k Ω
Line :  150 mV/ 25 k Ω
Controls:
Bass :  +12/-15 dB at 50 Hz
Mid :  +5,5/-6 dB at 10 kHz
High :  +10/-9 dB at 10 kHz
Low Filter Attenuation:  3 dB at 20 Hz
Dimensions (W x H x D):  416 x 146 x 243 mm
Weight (net):  6,2 kg 

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